Chronic cough needs to be investigated for a cause
DEAR DR. ROACH: You once wrote a column on chronic cough and suggested a medication that might be useful in treating this. Would you please remind me of the drug name? I have an elderly mother who suffers daily with this affliction. She can no longer have a conversation or speak on the phone because of it; even activities of daily living are interrupted by these episodes. We have tried a number of options. Some have worked for a while, but nothing for any length of time. I would appreciate any info you could give me. -- J.N.
ANSWER: Severe cough like your mother's deserves a thorough workup, and although a regular physician can certainly handle most cases of cough, an expert is appropriate for the kind of cough that lasts for months and resists a diagnosis. Hopefully she can see a pulmonologist, although there are causes of cough outside the lungs, including the ear/nose/throat (postnasal drip) and stomach (acid reflux). Some drugs, especially ACE inhibitors, are well known to cause chronic cough.
I've had a very few cases of people who have had exhaustive evaluations with no answer. Some people have a neurological cause (laryngeal neuropathy), and have responded well to medication, such as gabapentin. I've had the rare patient in whom nothing has worked, and have tried an opiate cough suppressant, tramadol. This medication should not be used lightly, nor in a person with a history of substance abuse, and the ordering physician should carefully monitor treatment.
DEAR DR. ROACH: I have been reading about the new COVID-19 vaccines. Since at least some of these vaccines work by getting a person's own body to generate the antigen, what is to stop it from inducing an autoimmune response? -- F.M.
ANSWER: An autoimmune reaction is when the body reacts to its own cells. There are many autoimmune diseases: Type 1 diabetes, for example, is an autoimmune response to the cells that make insulin. Hashimoto's thyroiditis causes the body to attack thyroid-producing cells. In other autoimmune diseases, such as rheumatoid arthritis or systemic lupus erythematosus, the body response is much more complex. What triggers the body to start attacking its own cells and tissues is poorly understood in most cases.
At least two of the new COVID-19 vaccines use mRNA (for "messenger" RNA). This type of RNA takes genetic information from the DNA and brings it to the protein-making part of the cell. Think of DNA as a blueprint for making RNA, which is what is used to make proteins. This strand of RNA genetic material enters the body's cell and causes the person's own cells to make a particular viral protein, called the spike protein. Some spike protein is sent outside the cell, where it stimulates production of antibodies to the spike protein, which will help the body fight off COVID-19 if it gets exposed. In addition, the spike protein is also expressed on the cell surface in connection with proteins called MHC-1 complex. This combination stimulates the T-cells of the body to also be ready to fight off COVID-19-infected cells.
The mRNA is never taken up into the cell nucleus, and cannot become part of the person's own DNA. In fact, the mRNA is destroyed by the cell's own processes after the cell has made the spike protein. As such, the vaccine should not be able to trigger an autoimmune response, since it is causing a reaction to the spike protein, which no cells of the body normally express.
You can read more about m-RNA vaccines at www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/mrna.html